Blast gun



Nov. 2-1, 1939.

c. B. FLETCHER BLAST GUN Original Filed April l7, l9 7 2 Sheets-Sheet 1 ATTORNEY.

Nov. 21, 1939. c. B. FLETCHER Re. 21 ,275

' BLAST GUN Original Filed April 17, 1937 2 Sheets-Sheet 2 I N VENT OR.

ATTORNEYS.

04mm Pzzrc A sg'z Reiuued Nov. 21, 19 39 Y BLAST GUN Clarence B. Pletcher, Buchanan, Mich.

Original No. 2,107,084,

dated February 1, 1938,

Serial No. 137,576, April 17, 1937. Application for reissue April 28,

5 Claims.

This invention relates to sand blasting guns of the type using a high pressure of water for forcing a mixture of the water, sand and air from the nozzle of the gun on to the work or surface to be cleaned or sand blasted.

An object of the present invention is to provide a blasting gun of the character above mentioned characterized by improved means for insuring a thorough mixing of the water, sand and air.

To this end the gun is provided with a chamber into which sand and air is drawn by suction and into which water under pressure is introduced in a manner to set up a turbulence within the chamber conducive to. a thorough mixing of the water with the sand and air'to the end that there will be no choking of the orifices and as would otherwise occur due to a lack of a proper mixing 0 the water and sand.

A further object of the invention is to provide for such a mixing of the water and sand that cleaning of the gun will be necessary only occasionally and only after long periods of use.

The invention together with its objects and advantages will be best understood from a study of the following description taken in connection with the accompanying drawings wherein:

Figure 1 is a sectional view through a blast gun involving the features of the present invention.

Figure 2 is an elevational view of a let Flgui'e 3 is an enlarged fragmentary elevational view of the gun .at the handle end thereof.

Figure 4 is an end elevational view the gun viewing the same from the handle end thereof and Figure 5 is a perspective view of a yoke member.

Referring to the drawings by reference numer- 9.15 it will be seen that ingthe preferred embodiment thereof the gun comprises a barrel Shaving integral therewith a handle 6.

Barrel 5 is bored to provide a suction and mixing chamber 1 and a valve chamber 8. Chambers 1 and 8 are provided with a common .or partition wall 8 that has a bore therethrough which bore has a conical end Ill forming a valve seat and a threaded end I I into which latter end is threaded a ietanozzle H.

The handle 6 is provided with a. bore i3 that opens into the valve chamber 8 and at the free end thereof the handle 5 is provided with internal threads as at II for the coupling thereto of one end of a hose leading from a source of under pressure.

Fitted within the end of the barrel 5 equipped with the chamber 8 is a packing assembly ll held water 1938, Serial No. 204,924

in place between an internal shoulder l5 and a hollow gland nut l6.

Having a working iit through the packing assembly H is. a valve member ll providedat one end with a irusto-conical head It normally engaging the seat l0. Housed within the hollow of thegland nut i6 is a coil spring l9 which at one end bears against a shoulder 20 on the valve member il in a manner to yieldably retain the valve head l8 engaged with its seat It.

For retracting or unseating the valve ll there is provided a handle 2! which is forked at one end and at said end straddles the gun handle 6 and is pivoted to the handle 6 at opposite sides of the latter as at 22.

The legs of the handle 6 are substantially l..- shaped as shown in Figure 3 and at their free ends are pivoted as at 23 to the legs of a yoke 24 that at its closed end is provided with an opening 25 which loosely accommodates the stem of the valve 11.

On the outer end thereof the stem of valve H is threaded to receive a pair of stop nuts 26 with which the closed end of the yoke 24 cooperates for retracting or unseating the valve. In this connection it will be noted that at the closed end thereof yoke ll is provided with lugs or projections 2"! that have bearing engagement withthe nuts 25 in a manner shown in Figure 3 when the valve operating handle 2% is swung from the position shown in Figure 1 to the position shown in Figure 3 for unseating the valve i1. Obviouslyv upon release of pressure on handle it spring is will operate to seat the valve ll. Thus it will be seen that the valve ll maybe controlled by thesame hand holding the gun so that the other hand of the operator is left free.

The barrel '5 has formed integrally therewith and in the region of the chamberl, a nipple 28 that is suitably corrugated and is adapted to have sleeved thereon one end of a hose or flexible conduit leading from a source of sand supply which is fed by air pressure to the chamber 5 of the gun through said hose and the bore 2!? of the nipple 28. Due to the vacuum created in the chamber 1 by the water jet from nozzle ii, atmospheric air pressure is 'sumclent to feed the sand. The nipple 28 preferably extends from the top of the'chamber 1 to prevent water from entering the hose and thereby clogging the sand feed.

For the gun there is also provided a nozzle indicated generally by the reference numeral 30. Discharge nozzle 30 comprises a pair of complemental sections ll, 32. Section 3| is provided at one end with a threaded pin 33 that threads into the chamber equipped end I of the gun barrel.

' At its other end nozzle section 3| is provided with shoulder -38 provided integral with the nozzle section3l and the pin 34 of the nozzle section 32. At the intake end thereof the bore of the lining tube 36 is flared as at 39.

. from the gun.

Nozzle I2 is relatively small and is provided at one end with a threaded portion that threads into the end ll of the bore in the partition wall 9. The body of the nozzle I2 is provided with the aforementioned axial bore 35 which at the end thereof opening into chamber 8 is flared as shown.

Intermediate its ends the body of the nozzle i2 is provided with a diagonal port 40. Thus it will be seen that when valve I8 is unseated water from thesource of supply passes through the passage l3 in handle 6 into the chamber 8 and from chamber 8 through the bore 35 of nozzle l2 into the chamber l, certain of the water dis-. charging in a stream into the chamber I through the port 40 in nozzle l2 in a, manner to set up a turbulence and thoroughly agitate the mixture' This setting up of a turbulence within thechamber 1 will asabove mentioned, not only insure a thorough mixing of thesand and'water but will also-preclude accumulations of wet sand about the nozzle [2, within the chamber 1, and within the bore of the nozzle 30 and as would tend to obstruct the free flow ofwater andsand It is thought that a clear understanding of the construction, utility and advantages of an invention of this character will be had without a more detailed description.

Having thus described the invention, what is claimed as new is:

1. In a sand blast gun, a barrel provided with a partition, said barrel having a valve chamber on one side of the par'tion and a vacuum and mixing chamber at the opposite side of the partition, means for supplying water under pressure to the valve chamber, valve means associated with said partition and controlling the passage of water underpressure from the valve chamber to the mixing chamber, a nozzle carried by the partition and controlled by the valve means and which is provided with an axial bore and with a diagonal passage divergent in the direction of flow through both of which water under pressure passes when permitted by the valve means, the diagonal passage serving to set up a turbulence in the mixing chamber, means for supplying sand to the mixing chamber, and a nozzle carried by said barrel for discharging mixed sand and water therefrom.

2. In a blast device, a barrel having valve and mixing chambers and having an inlet for water under pressure leading into the valve chamber and having a lateral inlet leading into the mixing chamber, a nozzle leading from the valve chamber to the mixing chamber which has an axial passage and a diagonal passage divergent in the direction of ilow for a stream of water setting up turbulence in the mixing chamber, a valve controlling the nozzle, and means on the exterior of said device for operating said valve.

3. In a sand blast device, a part formed with a mixing chamber, means for supplying sand to said chamber, and valve-controlled means for supplying a stream of water under pressure to said chamber, said chamber having an outlet for mixed sand and water'under pressure, said valve controlled means including means for discharging an auxiliary stream of water at an angle divergent in the direction of flow to the first named stream of water into the mixing chamber to induce turbulence therein to provide thorough mixing of the sand and water therein,

4. A blast device comprising a barrel formed with a mixing chamber and with an inlet for a stream of water under pressure at one side there-- of and with an outlet at the opposite side thereof and with a lateral inlet discharging thereinto between said inlet and said outlet, said water inlet having means for discharging an auxiliary stream of water into the mixing chamber at an angle divergent in the direction of flow to the first-named stream of water to induce turbulence in the mixing chamber.

5. In a blast gun, a barrel provided with a partition, said barrel having a valve chamber on one side of the partition and a vacuum and mixing chamber at the opposite side of the partition, means for supplying water under pressure to the valve chamber, valve means associated with said partition and controlling the passage of water under pressure from the .valve chamber to the mixing chamber, a nozzle carried by the partition and controlled by the valve means and which is provided with an axial bore and with a diagonal passage divergent in the direction of flow through both of which water under pressure passes when permittedby the valve means, the diagonal passage servlngto set upa turbulence in the mixing chamber, an inlet opening atone side of the mixing chamber, and a discharge nozzle carried by said barrel.

CLARENCE B. FLETCHER. 

